JP2015529614A - Apparatus and method for producing phosgene - Google Patents

Abstract

The present invention provides a) a tube bundle, wherein the tube bundle is disposed in the reactor jacket (4) and has a plurality of reaction tubes (3), and the plurality of reaction tubes (3) are disposed substantially parallel to each other. And a tube bundle extending from the bottom tube sheet (1) to the upper tube sheet (2), and b) surrounding the reaction tube (3) together with the bottom tube sheet (1), the upper tube sheet (2), And a coolant chamber for the cooling fluid delimited by the reactor jacket (4), and an apparatus (R) for producing phosgene by reacting chlorine and carbon monoxide in the presence of a fixed bed catalyst. The tube bundle is surrounded by the annular space plate (7), the annular space plate (7) defining an inner annular space (12) for the passage of cooling fluid and the bottom tube plate (1) and the top An outer ring for passing liquid cooling fluid between the annular space plate (7) and the reactor jacket (4) at a distance from both of the tube plates Is paced (13) is formed, and wherein the outer annular space (13) is in fluid communication with the inner annular space (12) about the (R). Furthermore, the present invention relates to a method for producing phosgene using such an apparatus.

Description

  The present invention is a tube bundle disposed in a reactor shell and having a plurality of reaction tubes, wherein the plurality of reaction tubes are disposed substantially parallel to each other and extend from a bottom tube plate to an upper tube plate. And a cooling fluid refrigerant chamber surrounding the reaction tube and delimited by a bottom tube plate, a top tube plate, and a reactor shell, wherein chlorine and carbon monoxide are fixed bed. The present invention relates to an apparatus for producing phosgene by reacting in the presence of a catalyst. The invention further relates to a method for producing phosgene using the apparatus described above.

  It is known from the prior art (for example, Non-Patent Document 1) to produce phosgene from CO (carbon monoxide) and chlorine on an activated carbon catalyst in a tube bundle reactor. The stoichiometric excess of carbon monoxide is then passed over a fixed bed catalyst having a particle size of 3-5 mm, which is combined with chlorine and placed in a tube having an internal diameter of 50-70 mm. The Since chlorine can cause undesired reactions during subsequent use of phosgene, an excess of carbon monoxide is necessary to keep the free chlorine content in phosgene as low as possible.

  In order to cool the hot exothermic reaction with a production enthalpy of −107.6 kJ / mol, a cooling medium is guided around the catalyst tube. The reaction of CO and chlorine begins on a catalyst at about 40-50 ° C, the temperature in the tube rises to about 600 ° C and drops again to 40-240 ° C at the reactor outlet. Thereby, for example, a phosgene quality that meets the isocyanate production requirements is obtained. High starting material purity is particularly required for carbon monoxide. This is because the inclusion of methane and hydrogen as a result of production after carbon monoxide is combined with chlorine can cause a highly exothermic reaction with the production of hydrogen chloride. The temperature rise can cause a dangerous reaction between chlorine and equipment materials, the so-called chlorine / iron ignition.

  Phosgene is used as an adjunct or as an intermediate in many areas of chemistry. The largest field of use in terms of quantity is the production of diisocyanates as starting materials for polyurethane chemistry. In this case, mention may be made in particular with respect to the isomers of the substances 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate. Due to the dissociation equilibrium, 100 ° C. phosgene already contains about 50 ppm of chlorine. For example, in many fields of use such as the production of isocyanates for polyurethane production, such chlorine content already represents the upper limit of the specification, as disclosed in US Pat.

  As a result, many attempts have been made to improve phosgene production in terms of product quality and economy. Thus, U.S. Patent No. 6,057,051 describes a process for producing phosgene with reduced CO emissions or reduced CO loss by main bonding, subsequent condensation of phosgene, and subsequent bonding of residual gas and chlorine. Yes. As described in Patent Document 3, phosgene having a low carbon tetrachloride content can be obtained by using CO having a low methane content. U.S. Patent No. 6,057,034 provides a process with a control concept for minimizing CO excess.

  An important aspect in producing phosgene is the reliable and uniform dissipation of reaction heat. This is achieved by the cooling medium being guided around the reaction tube by forced convection or partially evaporated around the reaction tube by natural convection. U.S. Patent No. 6,057,034 describes a process that can be used to cool with both forced and free convection to generate steam. In one example, a reactor having 415 tubes arranged in parallel is mentioned.

  U.S. Patent No. 6,057,034 describes a process in which natural convection is used for cooling. Water is used as the cooling medium. Since the cooling medium must not enter the reaction chamber for corrosive reasons, the pressure of the cooling medium must in principle be lower than the pressure in the reactor, since leakage cannot be eliminated. U.S. Pat. No. 6,057,091 describes, inter alia, an apparatus comprising a tube bundle reactor and a separator for a partially evaporating cooling medium. In order to better cool large reactors, flow deflectors (baffle plates) have been described. However, it has been recognized as a disadvantage with this arrangement that in some cases the number of tubes is actually limited to about 3000 tubes.

  Patent Document 8 discloses a reactor equipped with a baffle plate for liquid heat exchanger medium inside. Thereby, more uniform heat dissipation is said to be achieved without increasing the amount of circulating heat exchanger media when the reactor diameter is large and the throughput is increased. The process is said to be particularly suitable for 1000 to 3500 contact tubes.

  Patent Document 9 relates to a similar technique, and the above process is said to be particularly suitable for a reactor having 2000 to 6000 contact tubes that perform direct cooling.

  Another phosgene reactor with increased capacity is known from US Pat. In this reactor, the baffle plates for the cooling medium are arranged in such a way that the cooling medium is guided in alternating sections perpendicular to the tubes filled with catalyst. In addition, reaction tubes are not arranged in some areas for reasons related to flow. Also in this case, the number of reaction tubes is generally 1000 to 3500.

  The need to produce larger capacities in an economical way means that a large number of lines should be avoided, instead increasing the flow rate through a single reactor. The problem that arises at that time is that it is necessary to ensure that each individual tube in the tube bundle reactor is cooled. Evaporative cooling by free convection is an efficient process and can be used for that purpose. However, sufficient cooling with free convection requires that each individual tube be supplied with sufficient cooling medium over the entire length to be heated. In the case of starting materials flowing from the bottom into the tube bundle reactor, it is particularly difficult to do so in the region directly above the bottom tube sheet. This is because a relatively large amount of heat must be dissipated there.

European Patent No. 0134506 European Patent No. 2067742 EP 1135329 International Publication No. 2010/103029 Pamphlet European Patent No. 0134506 European Patent No. 1640341 European Patent No. 1640341 International Publication No. 2010/076209 Pamphlet International Publication No. 2010/076208 Pamphlet EP 1485195

Ullmann's Encyclopedia of Industrial Chemistry, 5th Ed. Vol. A 19p 413f., VCH Verlagsgesellschaft mbH, Weinheim, 1991

  The object of the present invention is to improve the cooling efficiency of a device of the type mentioned at the beginning, especially when operating in free convection. Similarly, an object of the present invention is to allow such efficient cooling to be used even in a relatively large reactor having a large number of reaction tubes.

The objects are: a) a tube bundle arranged in the reactor shell and having a plurality of reaction tubes, the plurality of reaction tubes being arranged substantially parallel to each other and from the bottom tube plate to the upper tube plate An extended tube bundle,
b) a refrigerant chamber for the cooling fluid surrounding the reaction tube and delimited by the bottom tube plate, the top tube plate, and the reactor shell;
And is achieved by an apparatus for producing phosgene by reacting chlorine and carbon monoxide in the presence of a fixed bed catalyst,
The apparatus includes a tube bundle surrounded by an annular plate, the annular plate defining an inner annulus for passing cooling fluid and at a distance from both the bottom tube plate and the upper tube plate. An outer annular portion for allowing liquid cooling fluid to pass therethrough is formed between the plate and the reactor shell, and the outer annular portion is in flow communication with the inner annular portion.

  The present invention is based on the discovery that an efficient reaction of the reaction tubes in the tube bundle reactor can be achieved by surrounding the entire tube bundle with an annular plate. As a result, an inner annular portion is defined, and reaction heat is transferred from the reaction tube to the liquid cooling fluid in the inner annular portion. As a result of the heating, the cooling fluid is carried upwards by convection. The flow is channeled by an annular plate so that the cooling fluid flows uniformly and rapidly around the reaction tube. Thereby a part of the cooling fluid can be evaporated.

  When reaching the upper edge of the annular plate, the liquid cooling fluid still flows over this edge and returns again in the direction towards the bottom reactor plate via the outer annular part, thereby closing the cooling fluid circuit. Similarly, the annular plate again functions to guide the cooling fluid, which flows in a jacket-like orientation on the outside of the annular plate. The annular plate further allows separation from the cooling fluid flow in the reactor within the annular plate mounting area, so that turbulence caused by liquids flowing too close to each other effectively reduces convection. Although it may interfere, it is avoided.

  Thus, the device according to the invention can be operated in free convection, i.e. even if one or more pumps can be additionally provided, the pump is not essential for normal functioning. In other words, the device according to the present invention functions even when the power supply is lost, and as a result the risk of failure is greatly reduced, which is particularly important for toxic phosgene. This is a considerable advantage.

  In principle, any cooling fluid known to those skilled in the art that can be used for phosgene production, for example water, or even decalin, can be used as the cooling fluid.

  A typical catalyst is used as a fixed bed catalyst, for example an activated carbon catalyst known per se with a suitable particle size, eg 3-5 mm.

  For the annular plate, in principle, any material that would otherwise be used in the construction of the phosgene reactor can be selected, for example alloy steels conventionally used for that purpose. The thickness of the annular plate is, for example, about 0.5 to 1.0 cm. The annular plate preferably has a cylindrical shape.

  The distance from the bottom and top reactor plates to the annular plate can vary within a certain range. The distance from the bottom reactor plate, on the other hand, is selected so that a sufficient flow rate of cooling fluid is achieved, in order to sufficiently cool the reaction tube, especially in the highly stressed area directly above the bottom reactor plate. Is done. To that end, the distance from the bottom reactor plate to the annular plate should not be selected excessively, as the flow rate will decrease excessively as a result. However, if the distance is too small, the mass flow rate will be reduced and therefore the optimum distance will ultimately depend on the dimensions of the reactor. However, the optimal distance can be determined by several tests and corresponding calculations.

  In a preferred form of the device according to the invention, at least one downcomer for passing the liquid cooling fluid in the direction towards the bottom reactor plate is arranged in the tube bundle, in particular in the center of the tube bundle. The downcomer has an inner diameter of 20-50 cm, for example. The downcomer is in particular arranged such that the downcomer projects beyond the upper edge of the annular plate. The exact arrangement takes into account the resulting overflow height. This structural measure makes it possible to control the proportion of the cooling fluid guided downwards through the downcomer, with the majority of the cooling fluid largely flowing through the outer annulus. At the bottom edge of the outer annular portion, the downcomer can be flush with the bottom edge of the annular plate.

  The device according to the invention can in principle have any outer shape, for example a substantially circular cross section. That is, the device has a substantially cylindrical shape.

  The reaction tube has a typical diameter of, for example, 30-70 mm. The apparatus according to the invention can be provided in particular with a large number of reaction tubes. Thus, efficient cooling of the reactor can still be achieved using more than 4000, preferably 9000, or even 12,000 tubes. Nevertheless, the present invention is not limited to such large reactors and can be similarly configured with a smaller number of tubes.

  The apparatus according to the invention is particularly suitable for the production of phosgene, and it is possible to use the reactor for other processes in which heat of reaction is to be dissipated from the tube bundle reactor.

  Preferably, the tube bundle in the device according to the invention is divided into at least two tube bundle segments, in particular symmetrical tube bundle segments, between which the cooling fluid channel is provided in at least a plurality of sections, the cooling fluid channel comprising at least It has a width corresponding to the diameter of the reaction tube, preferably starting from an annular plate and extending into the tube bundle. In that way, the cooling of the tube bundle can be further improved. Especially when combined with an annular plate, the cooling fluid channel below the bottom edge of the annular plate allows the cooling fluid to flow more easily in the direction towards the center of the tube bundle, so that the heat of reaction is notably reduced at the bottom. It is more reliably dissipated in the critical area directly above the reactor plate.

  The cooling fluid channel may extend to the center of the tube bundle, ie the downcomer, and preferably at least two cooling fluid channels are so configured. However, it can also be provided that the cooling fluid channel extends over a length of ¼ to ¾ of the distance from the annular plate to the center of the tube bundle.

  At least one of the cooling fluid channels, preferably at least two, extend to the center of the tube bundle, and the cross section of those cooling fluid channels is narrowed in particular towards the center of the tube bundle, the narrow portion preferably being a step It takes the form of It is particularly preferred that the cooling fluid channels extend alternately to the center of the tube bundle. Thereby, a particularly efficient cooling of the reaction tube can be achieved.

  The reactant may in principle be introduced into the apparatus according to the invention at the top, but in this case it is preferred that the inlet side of the reactant into the reaction tube is provided on the side of the bottom tube sheet.

  In another preferred form of the device according to the invention, at least one inlet opening for the fluid cooling fluid and at least one outlet opening for the gaseous cooling fluid are provided, the inlet opening being arranged in particular below the outlet opening. Yes.

  As mentioned above, it is preferred that the device according to the invention can be operated using free convection and by boiling operation. That means that as the cooling fluid rises in the inner annular portion, a portion of the cooling fluid evaporates and the liquid and gaseous cooling fluid pass through the upper edge of the annular plate and then separate. In order to release the gaseous cooling fluid, it is conceivable that in another form of the device according to the invention, the reactor shell is expanded to form a vapor belt in the upper region. This expansion can be achieved by an enlarged diameter relative to the reactor chamber located below. The outlet opening for the gaseous cooling fluid is arranged in the steam belt and is preferably provided in the upper tube sheet or on the upper side of the steam belt. The outlet opening can additionally be connected to a condenser in which the gaseous cooling fluid is condensed. The condenser can be liquid cooled or air cooled, which is preferred because such cooling continues to function even in the event of a power failure. The condenser is preferably connected to the inlet opening for the liquid cooling fluid via a return line.

  In another form of the device according to the invention, the steam belt is asymmetric and / or arranged asymmetrically with respect to the annular plate, the flow cross-section of the steam belt being maximum, especially in the region of the outlet opening. The steam belt has, for example, a circular cross section and can be biased from the center of the tube bundle to the side of the outlet opening. Alternatively or simultaneously, the vapor belt may have a form other than circular, such as an elliptical cross section, or an overhang in the region of the outlet opening. Ultimately, the only important factor is that in this case a radial flow with minimal velocity occurs in the refrigerant chamber, so that a better separation between the liquid and the gaseous cooling fluid is achieved. At that time, the flow velocity in the steam belt hardly increases in spite of an increase in the volume flow rate in the direction toward the outlet opening. As such, there are fewer droplets of liquid cooling fluid entrained, which results in a reduction of corrosion problems in the upper region of the reactor.

  The apparatus according to the present invention allows the cooling fluid to rise in a direction from the bottom tube sheet through the inner annular part toward the upper tube sheet, from which the cooling fluid is guided via the outer annular part. It is comprised so that it can return to. As already mentioned above, the device can have an associated cooling fluid circulation device, which can carry the cooling fluid from the bottom tube sheet through the inner annulus towards the upper tube plate. The cooling fluid is guided from the upper tube sheet through the outer annular part and can return to the bottom tube sheet.

The present invention is a process for producing phosgene by reacting chlorine and carbon monoxide in the presence of a fixed bed catalyst comprising:
a) a tube bundle disposed within the reactor shell and having a plurality of reaction tubes, wherein the plurality of reaction tubes are disposed substantially parallel to each other and extend from the bottom tube plate to the top tube plate The tube bundle,
b) a method of using an apparatus that surrounds a reaction tube and that is defined by a bottom tube plate, a top tube plate, and a refrigerant chamber for a cooling fluid defined by a reactor shell;
In this method, the tube bundle is surrounded by an annular plate, the annular plate defines an inner annular portion for the passage of cooling fluid, and at a distance from both the bottom and upper tube plates. An outer annular portion for passing liquid cooling fluid is formed between the annular plate and the reactor shell, the outer annular portion is in flow communication with the inner annular portion, and the cooling fluid is at the bottom Ascending in the direction from the tube plate to the upper tube plate through the inner annular portion, the cooling fluid is guided from the upper tube plate through the outer annular portion to return to the bottom tube plate.

  The method according to the invention is preferably operated as evaporative cooling in which part of the cooling fluid evaporates by boiling.

  When water is used as the cooling medium, the penetration of the cooling medium into the reaction chamber must be avoided even when the reaction tube is not airtight. To do so, the pressure in the reaction chamber must be kept higher than the pressure in the refrigerant chamber so that phosgene enters the refrigerant chamber but water does not enter the product chamber when damage occurs. The refrigerant chamber is monitored by an appropriate monitoring device in case of such damage, so that secondary damage is avoided.

  In the process according to the invention, the CO and chlorine streams used are 2 to 20%, particularly preferably 5 to 12% molar excess of CO in order to achieve a low chlorine content in phosgene. It is preferable. As the gas mixer, any commercial gas mixer such as an orifice mixer, a static mixer, or a rotary mixer may be used, but a special gas mixer may not be necessary with appropriate piping. The absolute pressure of the mixed gas in this case is preferably 1.5 to 10 bar, particularly preferably 2 to 5 bar.

  By proper selection of the refrigerant pressure, the refrigerant temperature, and thus the product outlet temperature, is reliably maintained below 100 ° C. The cooling of the tube bundle reactor via the refrigerant chamber and the water circuit connected to the refrigerant chamber via the inlet opening and the outlet opening is preferably 0.1 to 0.8 bar absolute pressure, particularly preferably 0.15 to 0.5 bar. It is preferably carried out with water at bar, most preferably between 0.2 and 0.3 bar. Thereby, the boiling temperature of water is 45-93.5 ° C. (0.1-0.8 bar), 55-80 ° C. (0.15-0.5 bar), or 60-70 ° C. (0. 2 to 0.3 bar). As a result, phosgene leaves the tube bundle reactor at temperatures below 100 ° C. The absolute pressure in the reaction tube is preferably 1.5 to 10 bar, particularly preferably 2 to 5 bar.

  However, when a chemically inert cooling medium is used, the pressure of the cooling medium may be higher than the pressure in the reaction tube. A highly pressurized stream can be generated in the downstream condenser.

  Hereinafter, the present invention will be described in more detail with reference to FIGS. 1 and 2 and exemplary embodiments 1 and 2.

1 is a side sectional view of a device according to the present invention. It is the figure which looked at the cross section of the apparatus based on this invention of FIG. 1 from upper direction.

  FIG. 1 shows an apparatus R according to the invention in the form of a tube bundle reactor for producing phosgene by reacting chlorine and carbon monoxide in the presence of a fixed-bed catalyst. . The apparatus R comprises a reactor chamber, which is bounded in the bottom region by a bottom reactor plate 1 and in the top region by a top reactor plate 2 and a reactor shell 4. The boundaries are set. A plurality of reaction tubes 3 are disposed in the reactor chamber, the plurality of reaction tubes 3 being combined to form a tube bundle and filled with a fixed bed catalyst in the form of a granular activated carbon catalyst. Yes. For the purpose of clarifying the representation of FIG. 1, only one reaction tube 3 is shown.

  The starting materials for the reaction, namely chlorine and carbon monoxide, are introduced into the reaction tube 3 at the bottom and flow upward through the reaction tube 3 in the flow direction a, where an exothermic reaction to phosgene takes place. The tube bundle comprising the reaction tubes 3 is surrounded by an annulus plate 7, which defines an inner annular part 12 for the passage of cooling fluid, for example water. The annular plate 7 is made of, for example, a steel sheet and is separated from the bottom tube plate 1 and the upper tube plate 2. Further, an outer annular portion 13 for allowing liquid cooling fluid to pass therethrough is formed between the annular plate 7 and the reactor shell 4, and the outer annular portion 13 is in flow communication with the inner annular portion 12. ing.

  The distance from the bottom tube plate 1 to the annular plate 7 is achieved on the one hand, with a sufficiently fast cooling fluid flow above the bottom tube plate 1 on the other hand, without excessively reducing the mass flow rate of the cooling fluid in the region. Selected to be.

  At the center of the tube bundle, a down tube 6 is disposed for passing the liquid cooling fluid. The downcomer 6 projects from the upper edge of the annular plate 7 and divides the cooling fluid flow through the downcomer 6 and the outer annular part 13 into a targeted manner according to the height of the projecting part. Is possible. In this case, the downcomer 6 ends in the bottom region on the same plane as the lower edge of the annular plate 7.

  Below the upper reactor plate 2, a steam belt 5 is arranged, and the steam belt 5 is placed asymmetrically in the reactor shell 4. An outlet opening 8 for gaseous cooling fluid is provided at the upper boundary of the vapor belt 5, and the outlet opening 8 is in this case connected to a condenser not shown. In the condenser, the gaseous cooling fluid is converted to liquid form and fed back to the circuit from the inlet opening 9 for liquid cooling fluid using an annular line. The phase boundary between the liquid and the gaseous cooling fluid is indicated by the dashed line 14.

  FIG. 2 shows a tube bundle reactor R according to the present invention in a cross section as viewed from above. In FIG. 2, the tube bundle reactor R comprises a plurality of reaction tubes 3, which are arranged parallel to each other in the longitudinal extension of the reactor and divided into individual tube bundle segments 15. You can see that. The tube bundle segment 15 is a very large and symmetrical segment that forms a circle, and the cooling fluid channel 10 is formed between the tube bundle segments 15. The cooling fluid channels 10 extend alternately to the center of the reactor, that is, downcomer 6, and the width of the cooling fluid channels 10 extending to downcomer 6 narrows in a stepped manner in region 11. The cooling fluid channel 10 that does not extend to the downcomer 6 has an extension that starts from the annular plate 7 and is about one third of the total distance from the annular plate 7 to the center of the tube bundle.

  During operation of the apparatus R shown in FIG. 1, chlorine gas and carbon monoxide flow in the direction a as described above, and the reaction to phosgene generates significant exotherm as a result of contact with the fixed bed catalyst. Accompanied. The reaction heat generated there is transferred to the cooling fluid in the reactor chamber and surrounding the reaction tube 3 via the outer wall of the reaction tube 3. Since the exotherm of the reaction to phosgene is most noticeable in the region directly above the bottom tube plate 1, i.e. the inlet region of the reaction tube 3, the cooling fluid is significantly heated in the inlet region of the reaction tube 3, so that Is carried upward in the direction b in the inner annular portion 12 by convection. Some of the cooling fluid also evaporates on it.

  When the gaseous cooling fluid reaches the upper edge of the annular plate 7, it separates from the liquid cooling fluid in the vapor belt 5 placed asymmetrically in the reactor shell 4. The flow rate of the gaseous cooling fluid is kept low by the particular configuration of the vapor belt, so that droplets of liquid cooling fluid are substantially not entrained at all. The gaseous cooling fluid is passed into the condenser via the outlet opening 8, where the gaseous cooling fluid is converted back into liquid form and from the inlet opening 9 for liquid cooling fluid through the annular line. To be supplied again to the circuit.

  When the cooling fluid channel 10 is provided in the tube bundle, the cooling fluid fed back via the outer annular portion 13 flows more easily in the direction toward the center of the tube bundle after passing through the bottom edge of the annular plate 7. As a result, particularly effective cooling is achieved in particular in the region directly above the bottom tubesheet 1.

(Evaporation of decalin to cool the tube bundle reactor for phosgene production)
The tube bundle reactor has a diameter of 4 m and comprises 8800 reaction tubes. The reaction tube has a length of 4 m and an outer diameter of 30 mm. A total of 9100 kW of heat of reaction must be dissipated. This is achieved by evaporating 111 t decalin at 2.3 bar. The mass flow rate of the internal circulation is about 4300 t / h. In the attached condenser, 17 t / h of steam is produced at 21 bar.

(Evaporation of water to cool the tube bundle reactor for phosgene production)
The tube bundle reactor has a diameter of 3.8 m and is equipped with 1900 reaction tubes. The reaction tube has a length of 4 m and an outer diameter of 60.3 mm. A total of 5500 kW of heat of reaction must be dissipated. This is achieved by evaporating 18.4 t decalin at 250 mbar. The mass flow rate of the internal circulation is about 2400 t / h.

DESCRIPTION OF SYMBOLS 1 Bottom tube plate 2 Upper tube plate 3 Reaction tube 4 Reactor shell 5 Steam belt 6 Downcomer tube 7 Annular plate 8 Outlet opening 9 Inlet opening 10 Cooling fluid channel 11 Narrow part 12 Inner annular part 13 Outer annular part 14 Liquid cooling fluid 14 Phase boundary 15 Tube bundle segment a Flow direction of reactant and product b to k Flow direction of cooling fluid R Apparatus

Claims (15)

a) a tube bundle arranged in the reactor shell (4) and having a plurality of reaction tubes (3), wherein the plurality of reaction tubes (3) are arranged substantially parallel to each other and are bottom tubes A tube bundle extending from the plate (1) to the upper tube plate (2);
b) refrigerant for cooling fluid surrounding the reaction tube (3) and delimited by the bottom tube sheet (1), the upper tube sheet (2) and the reactor shell (4) Room,
An apparatus (R) for producing phosgene by reacting chlorine and carbon monoxide in the presence of a fixed bed catalyst,
The tube bundle is surrounded by an annular plate (7), the annular plate (7) defines an inner annular portion (12) for the passage of cooling fluid, and the bottom tube plate (1) and the upper tube plate An outer annular part (13) is formed between the annular plate (7) and the reactor shell (4), at a distance from both of (2), and for passing a liquid cooling fluid, An apparatus wherein the outer annular portion (13) is in flow communication with the inner annular portion (12).   2. Device according to claim 1, characterized in that at least one downcomer (6) for the passage of liquid cooling fluid is arranged in the tube bundle, in particular in the center of the tube bundle.   Device according to claim 2, characterized in that the downcomer (6) projects beyond the upper edge of the annular plate (7).   4. A device according to any one of the preceding claims, characterized in that it has a substantially circular cross section.   The tube bundle is divided into at least two tube bundle segments (15), in particular symmetrical tube bundle segments (15), and cooling fluid channels (10) are provided between the tube bundle segments (15) in at least a plurality of sections; The fluid channel (10) has a width corresponding at least to the diameter of the reaction tube (3) and in particular starts from the annular plate (7) to the inside of the tube bundle, preferably the annular plate (7 The device according to any one of claims 1 to 4, characterized in that it extends over a length of 1/4 to 3/4 of the distance from the tube bundle to the center of the tube bundle.   At least one of the cooling fluid channels (10) extends to the center of the tube bundle, the cross section of the cooling fluid channel is narrowing in particular towards the center of the tube bundle, and the narrow portion (11) is 6. A device according to claim 5, preferably in the form of a step.   7. A device according to claim 6, characterized in that the cooling fluid channels (10) extend alternately to the center of the tube bundle.   The apparatus according to any one of claims 1 to 7, wherein an inlet side of the reactant into the reaction tube (3) is provided on the bottom tube sheet (1) side.   At least one inlet opening (9) for fluid cooling fluid and at least one outlet opening (8) for gaseous cooling fluid are provided, said inlet opening (9) being in particular below said outlet opening (8) 9. The device according to claim 1, wherein the device is arranged.   The reactor shell (4) is extended to form a vapor belt (5) in the upper region, and the outlet opening (8) for gaseous cooling fluid is arranged in the vapor belt (5). The outlet opening (8) is preferably provided in the upper tube sheet (2) or above the steam belt (5) and / or connected to a condenser. 9. The apparatus according to 9.   The steam belt (5) is asymmetrical and / or arranged asymmetrically with respect to the annular plate (7), the flow cross section of the steam belt (5), in particular in the region of the outlet opening (8) Device according to claim 10, characterized in that it is maximum.   12. Device according to claim 10 or 11, characterized in that the condenser is connected via a return line to the inlet opening (9) for liquid cooling fluid.   The apparatus can allow the cooling fluid to rise in a direction from the bottom tube sheet (1) through the inner annular portion (12) toward the upper tube sheet (2), and the upper tube sheet (2). The cooling fluid is configured to be guided through the outer annular part (13) to return to the bottom tube sheet (1). The device according to item.   The device has an associated cooling fluid circulation device that directs the cooling fluid from the bottom tube plate (1) through the inner annular portion (12) to the upper tube plate (2). Configured so that the cooling fluid can be guided from the upper tube plate (2) through the outer annular portion (13) and returned to the bottom tube plate (1). 14. A device according to any one of the preceding claims, characterized in that a) a tube bundle disposed in the reactor shell (4) and having a plurality of reaction tubes (3), wherein the plurality of reaction tubes (3) are disposed substantially parallel to each other and the bottom tube plate A tube bundle extending from (1) to the upper tube sheet (2);
b) refrigerant for cooling fluid surrounding the reaction tube (3) and delimited by the bottom tube sheet (1), the upper tube sheet (2) and the reactor shell (4) Room,
A process for producing phosgene by reacting chlorine and carbon monoxide in the presence of a fixed bed catalyst using an apparatus comprising:
The tube bundle is surrounded by an annular plate (7), the annular plate (7) defines an inner annular portion (12) for the passage of cooling fluid, and the bottom tube plate (1) and the upper tube plate An outer annular part (13) is formed between the annular plate (7) and the reactor shell (4), at a distance from both of (2), and for passing a liquid cooling fluid, The outer annular portion (13) is in flow communication with the inner annular portion (12), and the cooling fluid passes from the bottom tube sheet (1) through the inner annular portion (12) to the upper tube sheet ( 2) rising in the direction towards 2), the cooling fluid being guided from the upper tube sheet (2) through the outer annular part (13) and returning to the bottom tube sheet (1).

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